I. Field of the Invention
This invention relates to hand held infrared hair dryers. More particularly, this invention relates to such hair dryers having within a pan shaped housing, a low velocity axial fan between a perforated air diffuser and air inlet, also a quartz infrared radiation source shielded by and in front of the diffuser, between the diffuser and the air outlet. The pattern of the perforations prevents any substantial negative airflow.
II. Prior Art
Hand held infrared hair dryers are known. However, there are none which have an air diffuser which supports and shields the infrared source and substantially prevents negative airflow.
One such hand held infrared hair dryer is described in U.S. Pat. No. 4,323,761 issued Apr. 6, 1982. This hair dryer is pan shaped with a fan in the back part of the housing in an opening in an infrared reflector. The fan is driven by a motor in the front part of the housing. The reflector is circular and is provided with an opening in the center to allow the fan blades to turn. An annular infrared heating element is provided in front of the reflector to radiate heat past a front grill element. This hair dryer, while generally satisfactory does not have uniform airflow at the air outlet and has the disadvantage of negative airflow because some of the air returns into the front of the dryer causing uneven, inefficient heating of the hair.
Other radiant hair dryers are disclosed in the following patents:
Great Britain Pat. No. 924,139 issued Apr. 24, 1963; Meyer, U.S. Pat. No. 1,541,988 issued June 6, 1925; Martin, U.S. Pat. No. 1,961,722 issued June 5, 1934; Mauger, U.S. Pat. No. 1,006,767 issued Oct. 24, 1911 and Zellerman, U.S. Pat. No. 3,289,679 issued Dec. 6, 1966.
The use of perforated elements in hair dryers to allow airflow through the perforations is shown in Shelton, U.S. Pat. No. 1,760,997 issued June 30, 1930 and Riblett, U.S. Pat. No. 3,786,575 issued Jan. 22, 1974. The perforations, as depicted in these patents, are uniform in size and are not disclosed for the purpose of enhancing uniform airflow and preventing negative airflow. The Shelton and Riblett devices do not have a relatively large hole at the top of the perforated element because the fan blade is between that element and the motor. Thus these prior art devices did not have the same problem of very uneven airflow and negative airflow which are present in the hair dryers having a pan shaped housing.
Roys, U.S. Pat. No. 1,388,822 issued Aug. 23, 1921 discloses a heater having a perforated air diffuser. The perforations are largest near the outer periphery and smallest near the center. This results in negative airflow in the central area.